Immunogenicity and Safety of Booster Immunization of ZF2001 After Inoculation With Two Doses of BBIBP-CorV

Inclusion Criteria: * Healthy subjects over 18 years old, and can provide vaccination information to prove that they have completed 2 doses of inactivated novel coronavirus vaccine (BBIBP-CorV) within the past 3-9 months; * The subjects voluntarily participate in the research, sign the informed consent form, and can provide valid identification, understand and comply with the requirements of the study protocol; * Female subjects of childbearing age agree to use effective contraception from the start of the study to 2 months after vaccination. Exclusion Criteria: * Suspected or confirmed fever (fever ≥38.5℃) within 72 hours before enrollment, or axillary body temperature ≥37.3℃ on the day of enrollment; * Diastolic blood pressure ≥ 100 mmHg and/or systolic blood pressure ≥ 160 mmHg without or after drug control; * Have a history of previous infection with new coronary pneumonia or a positive nucleic acid test history; * Those who currently suffer from the following diseases: 1.Thrombocytopenia, any coagulation disorder, or receiving anticoagulant therapy, etc.; 2.History of congenital or acquired immunodeficiency or autoimmune disease; asplenia, or history of spleen surgery, trauma, or treatment with immunomodulatory agents within 6 months, such as: immunosuppressive doses of glucocorticoids (dose reference: equivalent or prednisone 20mg/day for more than one week); or monoclonal antibody; or thymosin; or interferon, etc.; 3.Those suffering from acute infectious diseases or…